In the existing liquid crystal display (LCD), a white light emitting diode (LED) is usually used as a backlight source, and the backlight required by a liquid crystal display panel is achieved by reasonably collocating the light guide plate and an optical film. As requirements for high color gamut, high color saturation and energy-saving by the people are higher and higher, solutions of implementing the white light source, high color gamut and high color saturation in the current backlight include: using a UV-LED cooperated with red, green and blue (RGB) fluorescent powder; using a blue LED cooperated with red and green (RG) fluorescent powder; using a blue LED cooperated with a green LED and a red LED and so on. These solutions all can improve the color gamut, while implementing them is harder, and costs are higher.
A Quantum Dot (QD) technology is a semiconductor nanomaterial structure technology to bound electrons in a certain range, and the QD is formed of super-small compound crystal having sizes in a range of 1-100 nm. In the QD technology, wavelengths of lights can be controlled by using the crystal having different sizes, so as to accurately control colors of the lights. Thus, QD materials are applied in the backlight module. A high-frequency spectrum light source is adopted (such as the blue LED) to replace a traditional white light LED light sources, under the irradiation of the high-frequency spectrum light source, the QD materials can be excited to generate lights of different wavelengths. The colors of synthetic lights can be regulated by adjusting the sizes of the QD materials, such that the backlight requirement of the liquid crystal display of the high color gamut can be achieved.
FIG. 1 is a backlight module using a QD glass tube in the existing conventional technology. Referring to FIG. 1, a blue LED 11 is disposed right opposite to a light incident surface 121 of a light guide plate 12, QD fluorescent powder is encapsulated in the glass tube to form a QD glass tube 13, wherein the QD glass tube 13 is disposed between the blue LED 11 and the light incident surface 121 of the light guide plate 12. Blue lights emitted from the blue light LED 11 are irradiated to the light incident surface 121 of the light guide plate 12 through the QD glass tube 13. However, since the QD fluorescent power is very sensitive to a temperature, when a method shown in FIG. 1 is adopted, the QD fluorescent powder suffers large heat, thereby reducing the color gamut of a product.